Load more (announce inserted results): checklist

Live demo: Open the Load more BEFORE/AFTER micro-demo

Common failure modes

Silent updates: more content loads, but nothing is announced.
Focus theft: focus jumps to a newly inserted item while the user was typing/reading elsewhere.
Inconsistent scroll position: the viewport “jumps” so people lose their place.
Keyboard trap by accident: auto-loading on scroll makes it hard to reach the footer or other page regions.

Prefer an explicit action: a Load more <button> (or pagination) instead of automatic infinite scroll.
Keep focus stable: after loading, keep focus on the button (or where it already was).
Announce changes in a polite live region: role="status" + aria-live="polite" + aria-atomic="true".
Use aria-busy="true" on the results region while loading, then set it back to false.
Make the message specific: “Loaded 10 more results. 30 total.”

If you must do infinite scroll, still announce updates and avoid moving focus unless the user explicitly requested it.
For long catalogs, pagination is often the most predictable option.
Test with keyboard only: Tab to the control, Enter/Space loads more, and tab order stays sane.